This patent application makes reference to and thereby incorporates all information found in U.S. patent Application Ser. No. 10/856,494 (now issued U.S. Pat. No. 7,618,432) and Ser. No. 10/846,613 (now issued U.S. Pat. No. 7,744,620) by Wesley Pedersen et al., particularly information found in the specification and drawings related to FIGS. 5A-5L. Also, this patent application makes reference to and thereby fully incorporates all information found in issued U.S. Pat. No. 7,951,111 and U.S. patent application Ser. No. 13/108,938 by William J. Drasler et al.
Currently cylindrically shaped balloons are used to perform valvuloplasty procedures wherein the stenotic aortic valve leaflets are dilated or pushed back into the space of the aortic sinus. This procedure is typically performed under fluoroscopic guidance while the heart is beating. Movement of the heart, flow of blood, and inaccuracies in fluoroscopic guidance do not allow for accurate placement of the valvuloplasty catheter across the aortic annulus and sinus.
Recently dogbone-shaped balloons have been presented (see U.S. patent application Ser. No. 10/856,494 by Wesley Pedersen) that provides for improved positioning across the aortic annulus and sinus. Also, dogbone-shaped balloons have been presented that are able to measure the diameter of the aortic annulus as well as indicate the compliance characteristics of the aortic annulus (see William J. Drasler, U.S. Pat. No. 7,951,111).
Transcatheter aortic valve implantation (TAVI) is currently being adopted as a method to treat stenotic aortic valve disease. In this procedure a stented aortic valve is placed across the aortic valve annulus and into the aortic sinus region to hold back the diseased native valve leaflets. The stent portion of these valves tends to have a round cross-sectional shape. The annulus, however, tends to have an oval or elliptical shape owing to its anatomical location between the pulmonary valve and the mitral valve. Placement of a round stent into the elliptical opening of the annulus tends to form a leak pathway for blood around the implanted valve at each end of the major axis of the elliptically shaped annulus.
In some instances the elliptical shape of the annulus is reformed into a circular shape with a specific diameter and perimeter as the TAVI device is implanted. For these patients whose annulus can be reformed, it is beneficial to know the dimensions of the annulus in a stretched condition such that a properly sized TAVI device can be implanted without leakage of blood and without causing dissection of the annulus. For those patients that have a more calcified or less compliant elliptical annulus, it would be beneficial for the physician to know under what level of pressure the elliptical will reform to a round shape, or alternately, if that patient is perhaps not a suitable candidate for a TAVI device.